1. Field of the Invention
The present invention relates to an image processing device and method, and an imaging device, and in particular to a technique of eliminating influence of a mixed color or the like between each of pixels of a mosaic image corresponding to a color filter array arranged on an imaging element of a single plate.
2. Description of the Related Art
Generally, in an imaging element having a mosaic color filter array, a mixed color is caused by light leaked from an adjacent pixel. In addition, in an imaging element having an element structure in which an amplifier is shared for each predetermined pixel group, a difference in an output characteristic occurs according to a position relation between the amplifier and each of the pixels.
There is a problem in which when a WB gain for white balance (WB) correction is calculated from a RGB color signal affected by a mixed color or the like, it is impossible to obtain an accurate WB gain.
A conventional technique of removing a mixed color component from a color signal including a mixed color component is described in Japanese Patent Application Laid-Open No. 2010-130583 (PTL 1).
An imaging device described in PTL 1 includes a coefficient table in which a correction coefficient related to a signal component mixed to each of pixels from peripheral pixels thereof is stored by being associated with each of positions of the pixels in a pixel array in which a plurality of pixels are arranged in a row direction and a column direction. The imaging device described in PTL 1 reads a corresponding correction coefficient from the coefficient table in accordance with a position of a correction object pixel so as to correct a signal of the correction object pixel by using signals of peripheral pixels thereof and the correction coefficient.
In addition, there is known a technique of effectively correcting a mixed color occurring in a captured image, caused by light incident on an imaging element at an angle, by using a simple method to perform white balance correction (Japanese Patent Application Laid-Open No. 2011-234231 (PTL 2)).
In an image processing device described in PTL 2, a white detection region is determined with respect to a black body radiation axis in a predetermined chromaticity coordinate space so that the image processing device estimates an ambient light source from an integral value of each of color components of pixels included in the white detection region. The image processing device described in PTL 2 has a feature of selecting a white detection region in accordance with a diaphragm value (F value) because an amount of mixed color components particularly depend on a size of a diaphragm.
Meanwhile, in a Bayer array known as a color filter array of an imaging element, responses of a Gr (green in an R row) pixel adjacent to an R(red) pixel in a side-to-side direction and a Gb (green in a B row) pixel adjacent to a B(blue) in the side-to-side direction should originally be the same, however, there is a problem to be solved, in which imbalance occurs between the “Gr” and the “Gb”. In addition, there is a problem to be solved, in which color shading occurs in a peripheral portion of an imaging region. A color solid state imaging device described in Japanese Patent Application Laid-Open No. 2009-088255 (PTL 3) is configured to change a size (area) of a micro-lens for condensation provided on a color filter for each pixel by the pixel to solve the problem to be solved.